<template>
  <div class="swiper-container" ref="smallImg">
    <div class="swiper-wrapper">
      <div class="swiper-slide" v-for="(item,index) in imageList" :key="item.id">
        <!-- 这里使用了一个点击切换类名套路 -->
        <!-- 就是先绑定一个点击事件 传入一个小图的索引值 -->
        <!-- 写一个动态类名  将大图索引 == 小图索引就可以 -->
        <img :src="item.imgUrl" @click="handler(index)" :class="{active:currentIndex == index}">
      </div>
    </div>
    <div class="swiper-button-next"></div>
    <div class="swiper-button-prev"></div>
  </div>
</template>

<script>
  // 引入轮播图插件
  import Swiper from 'swiper'
  export default {
    name: "ImageList",
    props: ['imageList'],
    // 设置动态属性索引值
    data() {
      return {
        currentIndex:0
      }
    },
    watch: {
      imageList() {
        // 组件实例的方法$nextTick
        this.$nextTick(() => {
          new Swiper(this.$refs.smallImg, {
            // 设置展示数量 可以控制展示几张图
            slidesPerView: 3,
            // 设置切换数量 切换几张图一组
            slidesPerGroup: 2,
            // 如果需要前进后退按钮
            navigation: {
              nextEl: '.swiper-button-next',
              prevEl: '.swiper-button-prev',
            },
          })
        })
      }
    },
    methods:{
      // 类名切换回调
      handler(index){
        this.currentIndex = index;
        // 通过全局事件总线 通知兄弟当前显示第几张图
        this.$eventBus.$emit('send',index)
      }
    }
  }
</script>

<style lang="less" scoped>
  .swiper-container {
    height: 56px;
    width: 412px;
    box-sizing: border-box;
    padding: 0 12px;

    .swiper-slide {
      width: 56px;
      height: 56px;

      img {
        width: 100%;
        height: 100%;
        border: 1px solid #ccc;
        padding: 2px;
        width: 50px;
        height: 50px;
        display: block;

        &.active {
          border: 2px solid #f60;
          padding: 1px;
        }

        // 以上小图时出现边框
        // &:hover {
        //   border: 2px solid #f60;
        //   padding: 1px;
        // }
      }
    }

    .swiper-button-next {
      left: auto;
      right: 0;
    }

    .swiper-button-prev {
      left: 0;
      right: auto;
    }

    .swiper-button-next,
    .swiper-button-prev {
      box-sizing: border-box;
      width: 12px;
      height: 56px;
      background: rgb(235, 235, 235);
      border: 1px solid rgb(204, 204, 204);
      top: 0;
      margin-top: 0;

      &::after {
        font-size: 12px;
      }
    }
  }
</style>